In the construction of various types of buildings, factories, and other commercial structures, extensive networks of cables and conduits are needed for a variety of purposes. Such purposes may include the provision of electrical power, the transmission of communication and data signals, and the transportation of fluids such as gases or liquids. Such transmission is achieved via the use of electrical cables and other conduits which are routed throughout the structure. It can be appreciated that due to the size, number and complexity of cables and conduits which are used in many modern commercial structures, the efficient routing of such cables and conduit may be rendered difficult.
In order to effectively manage the routing of such cables and conduits, the art has seen the use of cable tray systems. As defined by the National Electrical Code, a cable tray system is an assembly of units or sections and associated fittings forming a rigid structural system used to support cables.
Cable tray systems may take a variety of shapes and forms but common to all such systems are a pair of spaced apart elongate side walls or rails between which the cables or conduits are supported. The cables or conduits may be secured to solid bottom trays (troughs) or spaced apart rungs which span the side rails and provide a surface on which the cables or conduits may be mounted. The cable tray may be supported at various levels above ground by use of overhead supports, floor-mounted supports or by extending the tray along the wall of a structure. The cable trays are permitted to extend transversely through partitions in walls to permit routing of cables and conduits to various locations within the structure. Examples of various types of cable trays are shown and described in the following patents: U.S. Pat. Nos. 3,022,972; 3,035,800; 3,042,351; 3,521,843; 3,618,882; 3,680,817; 3,791,613; 4,232,845; and 4,432,519.
In order to effectively route cables and conduits with a cable tray, the cables and conduits may be securely fastened within the cable tray. Such securement is desired to hold the cables or conduits in place and to prevent lateral shifting. This is typically accomplished by securing the cables or conduits to the trough or rungs extending between the spaced apart side rails. Cable tray systems include various accessory-hardware used to secure the cables and conduits to the trough or rungs supported between the side rails. As may be appreciated, with the wide variety of shapes, sizes and purposes for various cables and conduits, there is a need for various types of cable support accessory-hardware to secure the cables and conduits in the cable tray. In order to assure that all types of cable and conduit may be secured in a particular cable tray, the trough or rungs positioned between the side rails should include provisions for the accommodation of the various types of cable supports.
Support hardware such as pipe clamps, straps, clamps, cable ties and the like are all employed in certain situations to support a particular type of cable or conduit. However, many of the support trays of the prior art do not include the provision for the easy accommodation of different types of cable support hardware. This necessitates the installer, who is employing a cable or conduit not readily accommodated by the particular cable tray support hardware, to improvise when supporting such particular cable or conduit. In these situations, the cable or conduit may not be securely supported to the cable tray or may be supported in such a position that, over time, damage to the cable or conduit may take place.
In addition, with respect to a ladder-type cable tray or a ventilated type cable tray where spaces exist between the cable support surfaces of the cable tray, less surface area is available to securely support the cable between adjacent solid portions of the tray. It has been found that, especially with the ladder type cable trays of the prior art, there is insufficient surface area to suitably support a multiplicity of conduits and cable, especially where differing types of support hardware must be used within a single cable tray system.